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Abstract:

The present application provides a method and device for processing
inter-subframe service load balancing and processing inter-cell
interference, which includes: when processing the inter-subframe service
load balancing, determining a service load of a link in a time period;
determining a resource utilization ratio threshold according to the
service load; and transmitting service data in each subframe according to
the utilization ratio threshold. The inter-subframe service load
balancing is processed when the inter-cell interference is processed, and
in combination with various inter-cell interference coordination
technologies, interference mitigation in one of a frequency domain, power
and a space domain or the combination thereof is processed by the
interference coordination technology. The present application can relieve
the phenomenon that the interference mitigation effect is not good as the
load information can not adapt well to the dynamic change of the
inter-subframe service load in a time division duplex system, and can
further mitigate the inter-cell interference in a long term evolution
system, and improve the entire throughput performance of the system and
the service quality of the subscriber in the system.

Claims:

1. A method for processing inter-subframe service load balancing,
comprising: determining a service load of a link over a period of time;
determining a threshold of resource utilization ratio according to the
service load; and transmitting service data in respective subframes
according to the threshold of resource utilization ratio.

2. The method according to claim 1, wherein the amount of data
transmitted in all the subframes in the same link direction over a past
period of time is determined when the service load of the link over the
period of time is determined; and the threshold of resource utilization
ratio is determined according to an average usage condition of resources
in each subframe over the period of time when the threshold of resource
utilization ratio is determined according to the service load.

3. The method according to claim 1, wherein the amount of additional data
to be transmitted in a current link direction over a future period of
time is determined when the service load of the link over the period of
time is determined; and the threshold of resource utilization ratio is
determined according to the amount of additional data and the spectrum
ratio of a system when the threshold of resource utilization ratio is
determined according to the service load.

4. The method according to claim 3, wherein the amount of additional data
to be transmitted in each type of service or each type of RB in the
current link direction over the future period of time is determined when
the amount of additional data to be transmitted in the current link
direction over the future period of time is determined; and the threshold
of resource utilization ratio is determined according to the amount of
additional data to be transmitted and the transmission efficiency of each
type of service or each type of RB over the period of time when the
threshold of resource utilization ratio is determined according to the
amount of data. wherein the amount of additional data to be transmitted
in the current link direction over the future period of time is
determined by: making a statistic of the amount of service of downlink
data packets arriving of each RB over a period of time T, datai(n);
and determining a service transmission demand of the amount of additional
data to be transmitted in RBi over a future next period of time
nT˜(n+1)T, DATAi(n), according to datai(n), wherein
RBi with a different value of the subscript i represents a different
RB, wherein make
DATAi(n)=βdatai(n)+(1-.beta.)DATAi(n-1) or
DATAi(n)=datai(n) when the service transmission demand of the
amount of additional data to be transmitted in RBi over the future
next period of time nT˜(n+1)T, DATAi(n) is determined
according to datai(n), wherein β is a forgetting factor, and
DATAi(n-1) is a service transmission demand of the amount of
additional data to be transmitted in RBi over a period of time
before nT˜(n+1)T.

5. (canceled)

6. (canceled)

7. The method according to claim 4, wherein the transmission efficiency
of each type of service or each type of RB over the period of time is
obtained by: obtaining the number of PRBs used for RBi over a period
of time T, NPRBused(i,n), wherein RBi with a different value of
the subscript i represents a different RB; and determining the spectrum
efficiency of RBi, η i = SBR i N PRBused ( i , n
) , ##EQU00013## according to a service bit rate of RBi,
SBRi.

8. The method according to claim 4, wherein the threshold of resource
utilization ratio is determined according to the amount of additional
data to be transmitted and the transmission efficiency of each type of
service or each type of RB over the period of time by: determining a
downlink load threshold over a future next period of time
nT˜(n+1)T, Pth(n+1), in the equation of: P th ( n + 1
) = i = 1 N 1 η i × DATA i ( n ) N
PRBtotal , ##EQU00014## wherein NPRBtotal is the total number of
PRBs of all the subframes for downlink transmission of a Physical
Downlink Shared Channel, PDSCH, over the future next period of time
nT˜(n+1)T, DATAi(n) is a service transmission demand of the
amount of additional data to be transmitted in RBi over the future
next period of time nT˜(n+1)T, ηi is the spectrum
efficiency of RBi, N is the total number of RB, and RBi with a
different value of the subscript i represents a different RB, wherein the
downlink load threshold over the future next period of time
nT˜(n+1)T, Pth(n+1) is further determined in the equation of:
P th ( n + 1 ) = MAX { P th_min , i = 1 M 1
η i 1 × DATA i ( n ) N PRBtotal }
##EQU00015## where Pth.sub.--.sub.min is a lower limit of the
threshold of resource utilization ratio.

9. (canceled)

10. The method according to claim 3, wherein the amount of additional
data to be transmitted of each User Equipment, UE, in the current link
direction over the future period of time is determined when the amount of
additional data to be transmitted in the current link direction over the
future period of time is determined; and the threshold of resource
utilization ratio is determined according to the amount of additional
data to be transmitted and channel information of each UE when the
threshold of resource utilization ratio is determined according to the
amount of data, wherein the amount of additional data to be transmitted
in the current link direction over the future period of time is
determined by: making a statistic of the amount of service of downlink
data packets arriving of each UE over a period of time T,
datai1(n); and determining a service transmission demand of the
amount of additional data to be transmitted in each UE over a future next
period of time nT˜(n+1)T, DATAi1(n), according to
datai1(n), wherein make
DATA.sup.1.sub.i(n)=βdata.sup.1.sub.i(n)+(1-.beta.)DATA.sup.1.sub.i(-
n-1) or DATA.sup.1.sub.i(n)=data.sup.1.sub.i(n) when the service
transmission demand of the amount of additional data to be transmitted in
each UE over the future next period of time nT˜(n+1)T,
DATAi1(n), is determined according to datai1(n),
wherein β is a forgetting factor, and DATA.sup.1.sub.i(n-1) is a
service transmission demand of the amount of additional data to be
transmitted in each UE over a period of time before nT˜(n+1)T.

11. (canceled)

12. (canceled)

13. The method according to claim 10, wherein the channel information of
each UE over the period of time is obtained by: obtaining the number of
PRBs used by each UE over a period of time T, N.sup.1.sub.PRBused(i,n);
and determining the spectrum efficiency of each UE, η i 1 = SBR
i 1 N PRBused 1 ( i , n ) , ##EQU00016## according to a
service bit rate of each UE, SBR.sup.1.sub.i.

14. The method according to claim 10, wherein the threshold of resource
utilization ratio is determined according to the amount of additional
data to be transmitted and the channel information of each UE over the
period of time by: determining an uplink load threshold over a future
next period of time nT˜(n+1)T, P.sup.1.sub.th(n+1), in the equation
of: P th 1 ( n + 1 ) = i = 1 M 1 η i 1
× DATA i 1 ( n ) N PRBtotal , ##EQU00017## wherein
NPRBtotal is the total number of PRBs of all the subframes for
downlink transmission of a PDSCH over the future next period of time
nT˜(n+1)T, DATA.sup.1.sub.i(n) is a service transmission demand of
the amount of additional data to be transmitted in the UE over the future
next period of time nT˜(n+1)T, η.sup.1.sub.i is the spectrum
efficiency of each UE, and M is the total number of UEs, wherein the
uplink load threshold over the future next period of time
nT˜(n+1)T, P.sup.1.sub.th(n+1), is further determined in the
equation of: P th 1 ( n + 1 ) = MAX { P th_min , i
= 1 M 1 η i 1 × DATA i 1 ( n ) N PRBtotal
} ##EQU00018## wherein Pth.sub.--.sub.min is a lower limit of
the threshold of resource utilization ratio.

15. (canceled)

16. The method according to claim 1, wherein the length of the period of
time is set depending on a period in which a statistic of a service load
level in interference coordination is made when the service load of the
link over the period of time is determined, wherein an uplink static
period is set to be consistent with or equivalent to an update period of
High Interference Indicator, HII, and a downlink static period is set to
be consistent with or equivalent to an update period of
Relative-narrowband Tx Power indicator, RNTP, if a selected inter-cell
interference coordination technology is semi-static Inter-Cell
Interference Coordination, ICIC, when the statistic of the period of the
service load level is made.

17. (canceled)

18. A method for processing inter-cell interference, comprising the steps
of: performing an inter-subframe service load balancing process according
to claim 1; and performing an interference alleviation process in one or
a combination of the frequency domain, power and the space domain in
combination with various inter-cell interference coordination
technologies.

20. The method according to claim 18, further comprising: performing a
selection strategy in each resource dimension by a scheduler resulting
from one or a combination of a resource selection priority weight output
from the interference coordination technologies, channel information in
respective physical resource blocks and a threshold of resource
utilization ratio of inter-subframe load balancing.

21. A device for processing inter-subframe service load balancing,
comprising: a service load determining module configured to determine a
service load of a link over a period of time; a threshold determining
module configured to determine a threshold of resource utilization ratio
according to the service load; and a transmitting module configured to
transmit service data in respective subframes according to the threshold
of resource utilization ratio.

22. The device according to claim 21, wherein the service load
determining module is further configured to determine the amount of data
transmitted in all the subframes in the same link direction over a past
period of time when determining the service load of the link over the
period of time; and the threshold determining module is further
configured to determine the threshold of resource utilization ratio
according to an average usage condition of resources in each subframe
over the period of time when determining the threshold of resource
utilization ratio according to the service load, or the service load
determining module is further configured to determine the amount of
additional data to be transmitted in a current link direction over a
future period of time when determining the service load of the link over
the period of time; and the threshold determining module is further
configured to determine the threshold of resource utilization ratio
according to the amount of additional data and the spectrum ratio of a
system when determining the threshold of resource utilization ratio
according to the service load.

23. (canceled)

24. The device according to claim 22, wherein the service load
determining module is further configured to determine the amount of
additional data to be transmitted in each type of service or each type of
RB in the current link direction over the future period of time when
determining the amount of additional data to be transmitted in the
current link direction over the future period of time; and the threshold
determining module is further configured to determine the threshold of
resource utilization ratio according to the amount of additional data to
be transmitted and the transmission efficiency of each type of service or
each type of RB over the period of time when determining the threshold of
resource utilization ratio according to the amount of data wherein the
service load determining module comprises: an RB statistic unit
configured to make a statistic of the amount of service of downlink data
packets arriving of each RB over a period of time T, datai(n); and
an RB determining unit configured to determine a service transmission
demand of the amount of additional data to be transmitted in RBi
over a future next period of time nT˜(n+1)T, DATAi(n),
according to datai(n), wherein RBi with a different value of
the subscript i represents a different RB, wherein the RB determining
unit is further configured to make
DATAi(n)=βdatai(n)+(1-.beta.)DATAi(n-1) or
DATAi(n)=datai(n) when determining the service transmission
demand of the amount of additional data to be transmitted in RBi
over the future next period of time nT˜(n+1)T, DATAi(n),
according to datai(n), wherein β is a forgetting factor, and
DATAi(n-1) is a service transmission demand of the amount of
additional data to be transmitted in RBi over a period of time
before nT˜(n+1)T, wherein the threshold determining module is
further configured to obtain the number of PRBs used for RBi over a
period of time T, NPRBused(i, n), and then determine the spectrum
efficiency of RBi, η i = SBR i N PRBused ( i , n
) , ##EQU00019## according to a service bit rate of RBi,
SBRi, when obtaining the transmission efficiency of each type of
service or each type of RB over the period of time, wherein RBi with
a different value of the subscript i represents a different RB.

25. (canceled)

26. (canceled)

27. (canceled)

28. The device according to claim 24, wherein the threshold determining
module is further configured to determine a downlink load threshold over
a future next period of time nT˜(n+1)T, Pth(n+1), in the
equation of: P th ( n + 1 ) = i = 1 N 1 η i
× DATA i ( n ) N PRBtotal ##EQU00020## when
determining the threshold of resource utilization ratio according to the
amount of additional data to be transmitted and the transmission
efficiency of each type of service or each type of RB over the period of
time, wherein NPRBtotal is the total number of PRBs of all the
subframes for downlink transmission of a PDSCH over the future next
period of time nT˜(n+1)T, DATAi(n) is a service transmission
demand of the amount of additional data to be transmitted in RBi
over the future next period of time nT˜(n+1)T, ηi is the
spectrum efficiency of RBi, N is the total number of RBs, and
RBi with a different value of the subscript i represents a different
RB, wherein the threshold determining module is further configured to
further determine the downlink load threshold over the future next period
of time nT˜(n+1)T, Pth(n+1), in the equation of: P th (
n + 1 ) = MAX { P th_min , i = 1 N 1 η i
× DATA i ( n ) N PRBtotal } ##EQU00021## wherein
Pth.sub.--.sub.min is a lower limit of the threshold of resource
utilization ratio.

29. (canceled)

30. The device according to claim 22, wherein the service load
determining module is further configured to determine the amount of
additional data to be transmitted of each UE in the current link
direction over the future period of time when determining the amount of
additional data to be transmitted in the current link direction over the
future period of time; and the threshold determining module is further
configured to determine the threshold of resource utilization ratio
according to the amount of additional data to be transmitted and channel
information of each UE when determining the threshold of resource
utilization ratio according to the amount of data, wherein the service
load determining module comprises: a UE statistic unit configured to make
a statistic of the amount of service of downlink data packets arriving of
each UE over a period of time T, datai1(n); and a UE
determining unit configured to determine a service transmission demand of
the amount of additional data to be transmitted of each UE over a future
next period of time nT˜(n+1)T, DATAi1(n), according to
datai1(n), wherein the UE determining unit is further
configured to make
DATAi1(n)=βdata.sup.1.sub.i(n)+(1-.beta.)DATA.sup.1.sub.i(-
n-1) or DATA.sup.1.sub.i(n)=data.sup.1.sub.i(n) when determining the
service transmission demand of the amount of additional data to be
transmitted in each UE over the future next period of time
nT˜(n+1)T, according to datai1(n), wherein β is a
forgetting factor, and DATA.sup.1.sub.i(n-1) is a service transmission
demand of the amount of additional data to be transmitted in each UE over
a period of time before nT˜(n+1)T, wherein the threshold
determining module is further configured to obtain the number of PRBs
used by each UE over a period of time T, N.sup.1.sub.PRBused(i,n), and
then determine the spectrum efficiency of each UE, η i 1 = SBR
i 1 N PRBused 1 ( i , n ) , ##EQU00022## according to a
service bit rate of each UE, SBR.sup.1.sub.i, when obtaining the channel
information of each UE over the period of time.

31. (canceled)

32. (canceled)

33. (canceled)

34. The device according to claim 30, wherein the threshold determining
module is further configured to determine an uplink load threshold over a
future next period of time nT˜(n+1)T, P.sup.1.sub.th(n+1), in the
equation of: P th 1 ( n + 1 ) = i = 1 M 1 η i
1 × DATA i 1 ( n ) N PRBtotal ##EQU00023## when
determining the threshold of resource utilization ratio according to the
amount of additional data to be transmitted and the channel information
of each UE over the period of time, wherein NPRBtotal the total
number of PRBs of all the subframes for downlink transmission of a PDSCH
over the future next period of time nT˜(n+1)T, DATA.sup.1.sub.i(n)
is a service transmission demand of the amount of additional data to be
transmitted in the UE over the future next period of time
nT˜(n+1)T, η.sup.1.sub.i is the spectrum efficiency of each UE,
and M is the total number of UEs1 wherein the threshold determining
module is further configured to further determine the uplink load
threshold over the future next period of time nT˜(n+1)T,
P.sup.1.sub.th(n+1), in the equation of: P th 1 ( n + 1 ) =
MAX { P th_min , i = 1 M 1 η i 1 × DATA i
1 ( n ) N PRBtotal } ##EQU00024## wherein
Pht.sub.--.sub.min is a lower limit of the threshold of resource
utilization ratio.

35. (canceled)

36. The device according to claim 21, wherein the service load
determining module is further configured to set the length of the period
of time depending on a period in which a statistic of a service load
level in interference coordination is made when determining the service
load of the link over the period of time, wherein the service load
determining module is further configured to set an uplink static period
to be consistent with or equivalent to an update period of HII and a
downlink static period to be consistent with or equivalent to an update
period of RNTP if a selected inter-cell interference coordination
technology is semi-static ICIC when making the statistic of the period of
the service load level.

37. (canceled)

38. (canceled)

39. (canceled)

40. (canceled)

Description:

[0001] This application claims priority from Chinese Patent Application
No. 201010132237.7 filed with the Chinese Patent Office on Mar. 26, 2010
and entitled "Method and device for processing inter-subframe service
load balancing and processing inter-cell interference", which is herein
incorporated by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates to the wireless communication
technology and particularly to a method and device for processing
inter-subframe service load balancing and processing inter-cell
interference.

BACKGROUND OF THE INVENTION

[0003] In order to lower inter-cell interference and further improve the
spectrum efficiency, the Fractional Frequency Reuse (FFR) technology has
been introduced to the Worldwide Interoperability for Microwave Access
(WiMAX) system, and an underlying idea thereof lies in transmission of
data between adjacent cells in a fractional frequency reuse mode. FIG. 1
is a schematic principle diagram of FFR, and as illustrated in FIG. 1, an
area denoted in a horizontal-line shape in the figure can be shared by
three adjacent cells without any limitation on transmission power, so the
area denoted in the horizontal-line shape is located in a frequency band
with a frequency reuse coefficient of 1; and in the left diagram of FIG.
1, areas denoted in a mesh shape of the three cells are located
respectively in different frequency bands, and the area denoted in the
mesh shape of any cell will not be used by other cells, so the areas
denoted in the mesh shape are located in frequency bands with a frequency
reuse coefficient of 3; and other frequency bands in the right diagram
than the frequency band where the area denoted in the horizontal-line
shape is located have a reuse coefficient of 3/2.

[0004] In the Long Term Evolution (LTE) system, in order to achieve
same-frequency networking as far as possible, the LTE standard decides
the adoption of the Inter-Cell Interference Coordination (ICIC)
technology and defines related load information, e.g., a High
Interference Indicator (HII), an Overload Indicator (OI), a
Relative-narrowband Tx Power indicator (RNTP), etc., to be exchanged via
an X2 interface (an interface between eNodeBs) in the ICIC technology. In
the ICIC technology, a decision on limiting the use of resources is made
based upon load information generated in a current cell and received load
information generated in an adjacent cell and is notified to a scheduler,
a power controller and other modules to achieve the purpose of inter-cell
interference coordination.

[0005] After receiving the decision on limiting the use of resources made
by an ICIC module, the scheduler, the power controller and the other
modules allocate frequency-domain resources and power resources for
respective scheduled users in the current cell in compliance with the
limitation to thereby coordinate/alleviate inter-cell interference.

[0006] As can be seen from the foregoing description, both the FFR
technology and the ICIC technology are implemented by limiting the use of
frequency resources and power resources of an adjacent cell, that is, the
foregoing solutions only focus on frequency-domain and power resources,
and take into account interference coordination over only these two
dimensions.

[0007] Furthermore, in a beam shaping-enabled cell, inter-cell
interference coordination/avoidance can be achieved in beam coordination
solutions which can be divided into static beam coordination, dynamic
beam coordination and scheduling and other solutions in accordance with
beam coordination modes and beam coordination periods, but a general idea
of beam coordination is to allocate mutually orthogonal time and
frequency resources for users in the same beam direction in adjacent
cells to thereby achieve the purpose of beam coordination, that is,
alleviating interference.

[0008] FIG. 2 is a schematic principle diagram of static beam coordination
which illustrating a static beam coordination solution, and in FIG. 2,
resources of an orthogonal frequency division multiplexing system are
divided into four mutually orthogonal sets, and users in respective cells
are also divided into four mutually orthogonal sets depending on
direction information of the users, and then beam coordination is
achieved by establishing a mapping relationship between the sets of users
and the sets of resources, where the mapping relationship between the
sets of users and the sets of resources satisfies the following
condition:

[0009] Resources belonging to different sets of resources are allocated to
the greatest extent for users belonging to the same set of directions in
adjacent cells to thereby achieve the purpose of allocating mutually
orthogonal resources for the users in the same direction in the adjacent
cells. In FIG. 2, direction information of users in areas numbered 1 and
2 belongs to the same set of users, and space-domain beam coordination to
avoid same-frequency interference can be achieved by allocating a
resource in a set of resources 1 for the users in the area numbered 1 and
allocating a resource in a set of resources 2 for the users in the area
numbered 2.

[0010] A drawback of the prior art lies in that in the foregoing various
interference alleviation solutions of the orthogonal frequency division
multiplexing system, either coordination over frequency-domain, power,
frequency and power resources alone or space-domain beam coordination
alone is taken into account, but these methods generally do not take into
account specific characteristics of the Time Division Duplex (TDD) system
and thus also do not take into account the specific characteristics of
TDD in combination with the foregoing solutions to achieve a solution to
joint interference alleviation in a plurality of resource dimensions.

SUMMARY OF THE INVENTION

[0011] A technical problem to be addressed by the invention is to provide
a method and device for processing inter-subframe service load balancing
and processing inter-cell interference.

[0012] An embodiment of the invention provides a method for processing
inter-subframe service load balancing, which includes the steps of:

[0013] determining a service load of a link over a period of time;

[0014] determining a threshold of resource utilization ratio according to
the service load; and [0015] transmitting service data in respective
subframes according to the threshold of resource utilization ratio.

[0016] An embodiment of the invention provides a method for processing
inter-cell interference, which includes the steps of:

[0017] performing an inter-subframe service load balancing process; and

[0018] performing an interference alleviation process in one or a
combination of the frequency domain, power and the space domain in
combination with various inter-cell interference coordination
technologies.

[0019] An embodiment of the invention provides a device for processing
inter-subframe service load balancing, which includes:

[0020] a service load determining module configured to determine a service
load of a link over a period of time;

[0021] a threshold determining module configured to determine a threshold
of resource utilization ratio according to the service load; and

[0022] a transmitting module configured to transmit service data in
respective subframes according to the threshold of resource utilization
ratio.

[0023] An embodiment of the invention provides a device for processing
inter-cell interference, which includes:

[0024] an inter-subframe load balancing module configured to perform an
inter-subframe service load balancing process; and

[0025] an inter-cell interference coordination module configured to
perform an interference alleviation process in one or a combination of
the frequency domain, power and the space domain in combination with
various inter-cell interference coordination technologies.

[0026] The advantageous effects of the invention are as follows:

[0027] When the inter-subframe service load balancing process provided in
the embodiment of the invention is performed, firstly a service load of a
link over a period of time is determined; and then a threshold of
resource utilization ratio is determined according to the service load;
and service data is transmitted in respective subframes according to the
threshold of resource utilization ratio. Since service data is
transmitted in respective subframes according to the threshold of
resource utilization ratio, the drawback that a service load fluctuates
with subframes in the TDD system can be addressed.

[0028] When the inter-cell interference process provided in the embodiment
of the invention is performed, an inter-subframe service load balancing
process is performed in combination with various inter-cell interference
coordination technologies by which an interference alleviation process in
one of the frequency domain, power and the space domain or a combination
thereof is performed. Since the drawback that a service load fluctuates
with subframes in the TDD system is addressed by an inter-subframe load
balancing algorithm, time-domain balance of an interference level is
achieved, and then interference coordination and alleviation in the
frequency domain, power and even the space domain can further be achieved
in combination with various interference coordination solutions.

[0029] As can be seen, the technical solutions according to the
embodiments of the invention can alleviate a phenomenon that a poor
interference alleviation effect may result from load information being
not well adapted to a dynamic variation of the service load across
respective subframes in the TDD system, and can further alleviate
inter-cell interference in the LTE system and improve the overall
throughput performance of the system and the service quality for users in
the system.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030]FIG. 1 is a schematic principle diagram of FFR in the prior art;

[0031] FIG. 2 is a schematic principle diagram of static beam coordination
in the prior art;

[0032]FIG. 3 is a schematic flow chart of performing a method for
processing inter-subframe service load balancing according to an
embodiment of the invention;

[0033]FIG. 4 is schematic flow chart of performing a method for
processing inter-cell interference according to an embodiment of the
invention;

[0034]FIG. 5 is a schematic structural diagram of a device for processing
inter-subframe service load balancing according to an embodiment of the
invention; and

[0035]FIG. 6 is a schematic structural diagram of a device for processing
inter-cell interference according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] In the process of making the invention, the inventors have noticed
that:

[0037] In a mobile communication system using the Orthogonal Frequency
Division Multiplexing (OFDM) transmission technology, e.g., the LTE
system, the WiMAX system, respective sub-carriers in cells are orthogonal
to each other, so the problem of intra-cell interference has been well
addressed. Thus for the orthogonal frequency division multiplexing
system, respective cells are subject to interference primarily including
two parts: intra-cell thermal noise and Inter-Cell Interference (ICI).
Traditional communication technologies and signal processing technologies
(e.g., match filtering) have well removed an adverse effect arising from
thermal noise. For inter-cell interference, a typical cellular mobile
communication system achieves the purpose of alleviating inter-cell
interference in a frequency reuse (that is, resources of different
frequency bands are used in adjacent cells) method, but this results
directly in a drawback that a utilization ratio of frequency resources is
low in the system.

[0038] An existing mobile communication system (e.g., the LTE system)
makes a high demand for the spectrum efficiency of the system and desires
a frequency reuse coefficient close to 1 as possible (that is, totally
the same frequency-domain resource is used in adjacent cells), and in
order to lower interference between the cells while considering the
amount of information exchanged between the cells, a delay of interaction
via an interface and other limiting factors, various OFDM systems
generally adopt corresponding inter-cell interference alleviation
solutions, for examples, the WiMAX system adopts the FFR solution, and
the LTE system finally adopts the semi-static ICIC technology for the
purpose of alleviating inter-cell interference and standardizes load
information exchanged between cells.

[0039] In the LTE system, load information of respective cells can be
exchanged via an X2 interface for the purpose of inter-cell
frequency-domain interference coordination and power interference
coordination. In the existing LTE standard, the Frequency Division Duplex
(FDD) system and the Time Division Duplex (TDD) system adopt the same
ICIC solution, and also the standard defines totally the same load
information.

[0040] For the time division duplex-orthogonal frequency division
multiplexing system, uplink and downlink communication links can not
coexist due to the use of the same frequency for the uplink and downlink
communication links. However, the arrivals of uplink and downlink service
are not limited by respective subframe communication link directions, and
specifically downlink data of respective users transmitted from a core
network may arrive even in an uplink subframe; and a service demand of a
User Equipment (UE) for uplink transmission may arrive even in a downlink
subframe. Therefore particularly for the TDD system, a phenomena of
accumulated downlink service will necessarily arise during uplink
transmission, and after an uplink subframe comes to an end, such a
situation tends to arise that an immediately following adjacent downlink
subframe is heavily loaded instantaneously, and for a plurality of
consecutive downlink subframes, the service load is distributed extremely
unevenly across the respective downlink subframes: assuming that there
are consecutive downlink subframes N, N+1 and N+2, and then such a
situation tends to arise that the downlink subframe N is heavily loaded
and the downlink subframe N+2 is lightly loaded. Furthermore, since
respective cells in the time division duplex LTE system are synchronous
and have generally consistent uplink and downlink subframe configuration,
service loads of a plurality of cells for same-frequency networking will
fluctuate consistently with respective subframes, and thus such a
situation tends to arise that a load level of the system fluctuates
sharply. This inter-subframe uneven distribution of a service load level
will cause an inter-cell interference level in the system to fluctuate
sharply with a varying service load: when there is a light service load,
a data transmission demand of current service can be satisfied in each
cell using only a small number of resources, and at this time inter-cell
interference coordination/avoidance can be well achieved by the ICIC
technology; and when there is a heavy service load, respective data
transmission demands have be accommodated in respective cells using a
large number of resources, and at this time a good interference
coordination effect can not be achieved even with the ICIC technology
defined in the standard, so inter-cell interference at this time will
still be maintained at a high level. When there is a lot of Guaranteed
Bit Rate (GBR) service, e.g., video streams, in the system, this feature
of a system load level fluctuating sharply with subframes will become
more prominent.

[0041] Furthermore, in view of a limited capacity and transmission delay
of an X2 interface, load information defined in the standard can not be
exchanged too frequently, so respective load information can be generated
only based upon an average load level and interference level of cells
over a period of time; and since the load information is obtained by
smoothing a service load over a period of time, resource allocation
restriction and adjustment information imposed on a scheduler in ICIC
will also apply to be averaged to a service load level of each subframe
instead of the service load level fluctuating with respective subframes
in the TDD system. Interference alleviation of the TDD system is achieved
depending on an inter-cell interference coordination strategy obtained
from such statistically even service load information, thus inevitably
restricting the performance of ICIC and making it very difficult to
achieve the purpose of lowering inter-cell interference and optimizing
the overall performance of the system.

[0042] A specific analysis will be made below.

[0043] For the static or semi-static FFR technology and Soft Frequency
Reuse (SFR) in the WiMAX system and the static/semi-static ICIC
technology of the LTE system, an interference coordination strategy is
determined in all of these technologies by pre-configuring or making a
statistic of service load levels of respective groups of users in cells
over a period of time.

[0044] In the LTE system, since no network entity for centralized control
exists at the side of an access network, the foregoing methods rely upon
an exchange of related load information via an X2 interface (an interface
between base stations), and in view of a limited capacity and a certain
exchange delay of the X2 interface, thus load information exchanged
between respective cells is very limited and updated at a long period in
such methods. ICIC related load information and the shortest update
periods thereof defined in the LTE standard are as follows: HII (20 ms),
OI (200 ms) and RNTP (200 ms), and as can be seen, the period of the
foregoing exchange of load information via the X2 interface is far larger
than a scheduling interval of the system (the scheduling interval of the
LTE system is 1 ms).

[0045] However, in the TDD system, since uplink and downlink subframes can
not coexist and the arrivals of service in respective directions is
independent from the direction of the current subframe, such a situation
that downlink data is accumulated in uplink subframes inevitably arises,
and taking the uplink and downlink subframe configuration 3 of the LTE
TDD system as an example, data is still transmitted from the core network
to base stations in uplink subframes 2, 3 and 4, so after the subframe 4
comes to an end, there is a lot of downlink data to be transmitted, and
thus a subframe 5 is heavily loaded; and as consecutive downlink
subframes arrive, the downlink data accumulated in the uplink subframes
is gradually transmitted, and thus loads of subframes 6, 7, 8 and 9 will
be gradually lowered. Since cells in the TDD system are synchronous, the
foregoing phenomenon will arise in all the cells, resulting in a very
high service load of the subframe 5 throughout the system and thus very
high same-frequency interference, where same-frequency interference
fluctuates sharply in the downlink subframes 5-9 in the system.

[0046] In the table, D is a downlink subframe, U is an uplink subframe,
and S is a special subframe.

[0047] Since a general idea of the foregoing FFR, static/semi-static ICIC
and beam coordination solutions is to avoid to the greatest extent
allocating mutually orthogonal resources for users possibly causing
strong interference instead of actively removing interference by the
means such as signal processing and the like, the method can play a good
role when the load of the system is not too heavy, but when there is a
very high service load level of the system, orthogonal resources can not
be achieved at this time, and such a situation that same-frequency
resources be used by interference-sensitive users in adjacent cells will
inevitably arise, thus inevitably resulting in great same-frequency
interference. Therefore in the example above, for the subframe 9, in the
case that an average load of the system is not too heavy, the service
loads of these subframes are very light, and a perfect interference
alleviation effect will necessarily be achieved in the existing
inter-cell interference coordination solutions; and for instantaneously
heavily loaded subframes, e.g., the subframe 5, inter-cell interference
can not be lowered effectively even if inter-cell interference
coordination is performed in the FFR, static/semi-static ICIC, beam
coordination and other solutions, so the performance of these subframes
will be degraded dramatically.

[0048] Furthermore, an interference alleviation scheduling strategy
generally is generated based upon an average load level over a period of
time in the FFR, static/semi-static ICIC, beam coordination and other
solutions in view of the amount of exchanged information and the
complexity of algorithmic calculation, that is, in the strategy, an
interference alleviation rule is generated by taking into account an
average load level of all the subframes in the same direction over each
link over a period of time, and this average load-based interference
alleviation rule is applied to respective subframes in the same direction
with sharply different loads in the TDD system, thus inevitably failing
to achieve a good interference alleviation effect.

[0049] In view of the foregoing two aspects, the existing FFR,
static/semi-static ICIC, beam coordination and other solutions can not
play a good role and fail to achieve an optimized interference
alleviation effect because the difference between loads of subframes in
the TDD system is not considered.

[0050] In view of the foregoing analysis, in embodiments of the invention,
an optimized solution to inter-cell interference alleviation will be
provided for the foregoing characteristics of the time division duplex
system, that is, uniform distribution of a system service load across
respective subframes in the same direction, that is, time-domain balance
of interference, is achieved in an inter-subframe load balancing
algorithm; then interference coordination/avoidance of different
frequency-domain resources in the orthogonal frequency division
multiplexing system is achieved in combination with the Inter-Cell
Interference Coordination (ICIC) technology for the purpose of
frequency-domain and power coordination; and if beam shaping is supported
in the system, then space-domain coordination can further be achieved in
combination with directivity of the beam shaping technology. Thus the
characteristics of the time division duplex system are fully considered,
and joint interference alleviation is achieved from the perspective of
the use of resources in a plurality of dimensions, e.g., time domain,
frequency domain, even space domain, power, etc. Thus a further optimized
interference alleviation effect can be achieved, the throughput of the
system and the performance of edge users can be further improved and the
Quality of Service (QoS) of users can be better guaranteed as compared
with a general interference alleviation solution.

[0051] Embodiments of the invention will be described below with reference
to the drawings.

[0052] Firstly in view of the foregoing analysis, the instantaneous
service load level in the TDD system has sharply different distribution
across different subframes, so only a very limited interference
alleviation effect can be achieved by the interference coordination
technology in some subframes. Furthermore, interference coordination
solutions, such as the FFR, static/semi-static ICIC, beam coordination
and the like, generally are performed by making an interference
alleviation decision based upon an average service load level of each
subframe over a period of time, so the accuracy of the interference
alleviation strategy in the respective subframes will inevitably be
influenced by using statically averaged load information over a period of
time to reflect instantaneously sharply different service load levels of
the respective subframes, thus also resulting in a poor interference
alleviation effect. Thus firstly a method for processing inter-subframe
service load balancing is proposed in an embodiment of the invention, and
in this solution service loads in the same link direction can be evenly
allocated to respective subframes in an inter-subframe load balancing
algorithm so as to address the problem of sharply different distribution
of the instantaneous service load levels across different subframes in
the TDD system.

[0053]FIG. 3 is a schematic flow chart of performing a method for
processing inter-subframe service load balancing, and as illustrated,
service load balancing can be processed in the following steps:

[0054] The step 301 is to determine a service load of a link over a period
of time;

[0055] The step 302 is to determine a threshold of resource utilization
ratio according to the service load; and

[0056] The step 303 is to transmit service data in respective subframes
according to the threshold of resource utilization ratio.

[0057] In an implementation, the foregoing solution can alone address
inter-subframe load balancing in the TDD system without necessarily being
combined with interference coordination but can achieve a better
interference alleviation effect in combination with interference
coordination.

[0058] When the service loads in the same link direction is distributed
evenly to respective subframes in an inter-subframe load balancing
algorithm in the foregoing solution, this can be performed respectively
depending on the past service loads and the future service loads,
particularly in the following modes.

[0059] Mode 1

[0060] When the service load of the link over the period of time, i.e.,
the amount of data transmitted on the link over the period of time, is
determined, the amount of data transmitted in all the subframes in the
same link direction over a past period of time can be determined; and

[0061] When the threshold of resource utilization ratio is determined
according to the service load, i.e., the amount of data, the threshold of
resource utilization ratio can be determined according to an average
usage condition of resources in each subframe over the period of time.

[0062] In an implementation, a statistic of resource usage conditions of
all the subframes in the same link direction over a period of time can be
made, and a current threshold of resource utilization ratio can be
determined according to the average resource usage condition, and when
scheduled resources are allocated, the resources actually used by each
subframe will not exceed the threshold of resource utilization ratio. In
this mode, the amount of transmitted data, i.e., the number of
transmitted bits, will not be considered, but only the number of used
resources, i.e., the number of used PRBs, will be considered for the
purpose of this mode.

[0063] Mode 2

[0064] When the service load of the link over the period of time, i.e.,
the amount of data transmitted on the link over a period of time, is
determined, the amount of additional data to be transmitted in a current
link direction over a future period of time can be determined; and

[0065] When the threshold of resource utilization ratio is determined
according to the service load, i.e., the amount of data, the threshold of
resource utilization ratio can be determined according to the amount of
the additional data and the spectrum efficiency of the system.

[0066] In an implementation, a statistic of the total amount of additional
data to be transmitted in the current link direction over a period of
time can be made, and a current threshold of resource utilization ratio
can be determined according to the amount of the additional data and the
spectrum efficiency of the system and taken as an upper limit of
allocated resources in subsequent resource allocation.

[0067] Mode 3

[0068] When the service load of the link over the period of time, i.e.,
the amount of data transmitted on the link over a period of time, is
determined, the amount of additional data to be transmitted over each
type of service or each type of Radio Bearers (RBs) in a current link
direction over a future period of time can be determined; and

[0069] When the threshold of resource utilization ratio is determined
according to the service load, i.e., the amount of data, the threshold of
resource utilization ratio can be determined according to the amount of
the additional data to be transmitted and the transmission efficiency of
each type of service or each type of RB over the period of time.

[0070] In an implementation, a statistic of the total amount of additional
data to be transmitted of each type of service or each type of RB in the
current link direction over a period of time and the transmission
efficiency of each type of service or each type of RB over the period of
time can be made, and a current threshold of resource utilization ratio
can be determined according to the total amount of the additional data to
be transmitted and the transmission efficiency and taken as an upper
limit of allocated resources in subsequent resource allocation.

[0071] In an implementation, the transmission efficiency is also the
spectrum efficiency, and the transmission efficiency of a certain kind of
service refers to the number of bits transmitted and the total number of
frequency resources used in the service over a period of time, so its
unit is bit/s/Hz in accordance with that of the spectrum efficiency.

[0072] Mode 4

[0073] When the service load of the link over the period of time, i.e.,
the amount of data transmitted on the link over a period of time, is
determined, the amount of additional data to be transmitted of each UE in
a current link direction over a future period of time can be determined;
and

[0074] When the threshold of resource utilization ratio is determined
according to the service load, i.e., the amount of data, the threshold of
resource utilization ratio can be determined according to the amount of
the additional data to be transmitted and channel information of each UE.

[0075] In an implementation, a statistic of the amount of additional data
to be transmitted of each UE in the current link direction over a period
of time can be made, and a current threshold of resource utilization
ratio can be determined according to the total amount of the additional
data and channel information of each UE and taken as an upper limit of
allocated resources in subsequent resource allocation.

[0076] In an implementation, a Channel Quality Indicator (CQI), Channel
State Information (CSI), etc., can be adopted as the channel information.

[0077] In the foregoing four modes, the mode 1 is based upon a historical
actual usage condition of resources, and the mode 2, the mode 3 and the
mode 4 are based upon a data transmission demand of a service. For the
mode 2, the mode 3 and the mode 4, only the performance of average
spectrum efficiency of the system and the like is considered in the mode
2; an allocation and a statistic are made based upon the mode 2 according
to the service type or the spectrum efficiency of RB in the mode 3; and
the threshold of resource utilization ratio is determined taking into
further account the factor of channel quality information of each UE and
the like in the mode 4. In the mode 1, the mode 2, the mode 3 and the
mode 4, the complexity of calculation ascends in sequence, the accuracy
of estimation also improves in sequence and the performance becomes
better in sequence.

[0078] Specifically, there is an inclusion relationship between "the total
amount of additional data to be transmitted in a current link direction
over a period of time" and "the total amount of additional data to be
transmitted in each type of service or each type of RB in a current link
direction over a period of time" in the mode 2 and the mode 3, that is,
"each type of service or each type of RB" is also a part of "additional
data in a current link direction", and the total amount of additional
data to be transmitted in a current link is the sum of the amount of
additional data to be transmitted of all the services (all the RBs).

[0079] Furthermore, in the mode 4, "the amount of additional data to be
transmitted of each UE in a current link direction over a period of time"
is also a part of "additional data in a current link direction", and the
total amount of additional data to be transmitted in a current link is
the sum of the amount of additional data to be transmitted of all the
UEs.

[0080] A difference between the mode 3 and the mode 4 lies in different
categorization of the total amount of additional data: consider which
service it belongs to, for example, a Voice over IP (VOIP) service, a
File Transfer Protocol (FTP) service or a World Wide Web (WWW) service,
no mater which UE the service is delivered to in the mode 3; and consider
which UE it belongs to without distinguishing whether it is an FTP
service or a WWW service of the UE in the mode 4.

[0081] Specific flows of performing the foregoing four modes are
substantially the same except for different objects in question and
assisting information in use. An implementation of the inter-cell load
balancing algorithm will be described below taking the mode 3 as an
example.

[0082] In an implementation, objects subject to load balancing are all the
subframes in the same direction in an interval of time T, and taking a
downlink subframe of the LTE system as an example, assuming that a
current downlink load threshold of the system is Pth(n), then a load
threshold of each downlink subframe is set to Pth(n) prior to
arrival of next time to update the load threshold so as to ensure that an
actual resource utilization ratio will not exceed the threshold in
frequency-domain scheduling.

[0083] 1. Assuming that there are N types of RB which can be categorized
by a QoS Class Indicator (QoS) class or logic channel attribution, then
all the RBs existing in the downlink direction can be traversed to obtain
data transmission demand and spectrum efficiency information of each RB.

[0084] 2. The amount of additional data to be transmitted in the current
link direction over the future period of time can be determined as
follows:

[0085] A statistic of the amount of service of downlink data packets
arriving of each RB over a period of time T, datai(n), is made,
where datai(n) with a different value of the subscript i represents
the amount of service of downlink data packets arriving of a different
RB; and

[0086] A service transmission demand of the amount of additional data to
be transmitted in RBi over a future next period of time
nT˜(n+1)T, DATAi(n), is determined according to datai(n),
where DATAi(n) is the amount of addition data to be transmitted in
RBi in a current link direction over a future next period of time,
and RBi with a different value of the subscript i represents a
different RB.

[0087] In an implementation, a statistic of the amount of service of
downlink data packets arriving of respective RBi over a period of
time T, datai(n), can be made at a Radio Link Control (RLC) layer or
a Packet Data Convergence Protocol (PDCP) layer, and a service
transmission demand of RBi over a next period of time
nT˜(n+1)T, DATAi(n) can be estimated according to the amount
of additional data.

[0088] When the service transmission demand of the amount of additional
data to be transmitted in RBi over the future next period of time
nT˜(n+1)T, DATAi(n), is determined according to datai(n),
the value may be smoothed using a forgetting factor filtering method or
may not be smoothed.

[0089] Specifically, let
DATAi(n)=βdatai(n)+(1-β)DATAi(n-1) when
smoothing is performed based on forgetting factor filtering, where β
is a forgetting factor, and DATAi(n-1) is a service transmission
demand of the amount of additional data to be transmitted in RBi
over a period of time (n-1)T˜nT.

[0090] Or let DATAi(n)=datai(n) when smoothing is not performed.

[0091] 3. The transmission efficiency of each type of service or each type
of RB over the period of time can be obtained as follows:

[0092] The number of Physical Resource Blocks (PRBs, the minimum unit of
resource allocation in an LTE system) used by RBi over a period of
time T, NPRBused(i,n), is obtained; and

[0093] The spectrum efficiency of RBi,

η i = SBR i N PRBused ( i , n ) , ##EQU00001##

is determined according to a service bit rate of RBi, SBRi.

[0094] In a specific implementation, the average transmission efficiency
of RBi in a current cell can be obtained by obtaining the number of
PRBs used by RBi over a period of time T, NPRBused(i,n), and
determining the spectrum efficiency of RBi,

η i = SBR i N PRBused ( i , n ) , ##EQU00002##

according to a service bit rate of RBi, SBRi, resulting from a
statistic, where the statistic of the Service Bit Rate (SBR) is made as
the amount of data actually transmitted over a period of time in the unit
of bit/s.

[0095] 4. The threshold of resource utilization ratio can be determined
depending on the amount of additional data to be transmitted and the
transmission efficiency of each type of service or each type of RB over
the period of time as follows:

[0096] A downlink load threshold over a future next period of time
nT˜(n+1)T, Pth(n+1), is determined in the equation of:

[0097] wherein NPRBtotal is the total number of PRBs of all the
subframes for downlink transmission of a Physical Downlink Shared Channel
(PDSCH) over the future next period of time nT˜(n+1)T,
DATAi(n) is the service transmission demand of the amount of
additional data to be transmitted in RBi over the future next period
of time nT˜(n+1)T, ηi is the spectrum efficiency, and N is
the total number of RBs.

[0098] In an implementation, when the downlink load threshold over the
future next period of time nT˜(n+1)T, Pth(n+1) is determined
in the equation, the threshold can be further determined in the equation
of:

[0099] wherein Pth--min is a lower limit of the threshold
of resource utilization ratio.

[0100] Specifically, Pth--min is a lower limit of the
threshold of resource utilization ratio, and the lower limit is set to
avoid an unnecessary limitation on resource allocation and a resulting
unnecessary loss of a frequency selectivity gain due to the threshold
being set too small when the average load of the system is very light.
Specifically, a typical value of Pth--min can be 1/3 or
1/4, and actually be guaranteed equivalent to an upper limit of a
resource utilization ratio of dissimilar-frequency networking, which can
be determined depending on a topology of a current network or the number
of cells strongly interfering adjacent cells among respective cells. For
example, the value can be set to 1/4 in the topology illustrated in FIG.
2.

[0101] In the mode 4, the channel information can be an CQI, CSI, etc.,
and it is essentially the same as the mode 3 in terms of determining the
threshold depending on the channel information, for example, firstly the
spectrum efficiency of each UE, ηi1, is determined, and
then Ptn1(n+1) is calculated from a service transmission demand
of the amount of additional data to be transmitted of each UE,
DATAi1(n), and the total number of used PRBs,
Ptn1(n+1), where

[0102] Wherein NPRBtotal is the total number of PRBs of all the
subframes for downlink transmission of a PDSCH over the future next
period of time nT˜(n+1)T, DATAi1(n) is a service
transmission demand of the amount of additional data to be transmitted of
the UE over the future next period of time nT˜(n+1)T,
ηi1 is the spectrum efficiency of each UE, and M is the
total number of UEs.

[0103] In an implementation, when a service load of a link over a period
of time, i.e., the amount of data transmitted on the link over a period
of time, is determined, the length of the period of time can be set
depending on the period in which a statistic of a service load level is
made in interference coordination. This is performed for the purpose of a
better implementation in combination with the inter-cell interference
coordination technology, and the length T of the statistic window can be
set to be consistent with the period in which a statistic of a service
load level is made in interference coordination: for example, an uplink
statistic period is set to be consistent with an update period of HII and
a downlink statistic period is set to be consistent with an update period
of RNTP in the LTE system.

[0104] As can be seen from foregoing embodiments, the threshold of
resource utilization ratio can be determined via inter-subframe load
balancing process as described above so that particularly a scheduler in
a base station can ensure that the foregoing threshold be strictly
observed in consecutive subframes in the same direction other than the
last subframe to thereby distribute a service load in the system evenly
to the respective subframes in the same direction.

[0105] As can be seen, the problem that a service load fluctuates with
respective subframes in the time division duplex system can be addressed
via inter-subframe load balancing process to thereby create an
advantageous condition for implementing the inter-cell interference
coordination technology.

[0106] After addressing the problem that the distribution difference of an
instantaneous service load level across different subframes is sharp in
the TDD system, an embodiment of the invention further proposes an
optimized interference alleviation solution for interference alleviation
of the time division duplex-orthogonal frequency division multiplexing
system, and an underlying idea thereof is as follows:

[0107] 1) Firstly a service load in the same link direction is distributed
evenly to respective subframes via an inter-subframe load balancing
algorithm to thereby achieve time-domain interference balance;

[0108] 2) Next interference alleviation, i.e., interference
coordination/alleviation in the frequency domain, power and the space
domain, in the respective subframes is further achieved in interference
coordination solutions such as the FFR, static/semi-static ICIC, beam
coordination and the like; and

[0109] 3). A scheduler of a base station comprehensively takes into
account strategies and limiting conditions resulting from the foregoing
sets of mechanisms to thereby create a resource allocation solution with
interference alleviation as well as joint optimization in a plurality of
resource dimensions.

[0110] Due to cooperation of the foregoing sets of mechanisms, an
embodiment of the invention provides an interference alleviation solution
with joint optimization in a plurality of resource dimensions for the
time division duplex-orthogonal frequency division multiplexing system to
thereby achieve a further optimized interference alleviation effect. A
specific implementation of the solution will be described below with
reference to the drawings.

[0111]FIG. 4 is a schematic flow chart of performing a method for
processing inter-cell interference, and as illustrated, inter-cell
interference can be processed in the following steps:

[0112] The step 401 is to perform an inter-subframe service load balancing
process; and

[0113] The step 402 is to perform an interference alleviation process in
one of the frequency domain, power and the space domain or a combination
thereof in combination with various inter-cell interference coordination
technologies.

[0114] In an implementation, the implementation of the step 401 can be
described with reference to the implementation of FIG. 3.

[0115] In an implementation, the interference coordination technologies in
the step 402 can include one or a combination of the following
technologies:

[0117] In the step 402, after the service load of the system is
distributed evenly to respective subframes in the same direction via the
inter-subframe load balancing algorithm, inter-cell same-frequency
interference of the respective subframes can be further alleviated in
combination with an inter-cell interference coordination algorithm
supported by a base station. After inter-subframe load balancing, further
interference alleviation can be performed in a series of solutions of the
FFR, SFR, static/semi-static ICIC, beam coordination and the like to
achieve an interference alleviation solution in a plurality of resource
dimensions with joint optimization of resources of the time domain, the
frequency domain, power and the space domain.

[0118] A specific implementation of the step 402 depends upon the
inter-cell interference coordination solution(s) implemented in
combination with the inter-subframe load balancing process, and in order
to better understand the implementation of both of the them in
combination, a solution of performing inter-subframe load balancing
combined with an interference alleviation rule of inter-cell interference
coordination in resource allocation of a scheduler will be introduced
below still taking the semi-static ICIC technology supported in the LTE
system as an example.

[0119] An interference alleviation rule generating module of the
semi-static ICIC technology can make a statistic of resource demands of
edge users and cell center users over a period of time to generate RNTP,
HII and other parameters of the current cell and actually measure uplink
interference levels in respective PRBs to generate an OI parameter; and
also the module receives HII, OI, RNTP information and other information
of an adjacent cell passed via an X2 interface (an interface between base
stations) and generates a resource selection priority weight
Pinter--ICIC of the current cell in accordance with an
algorithm set in the system, where the priority weight
Pinter--ICIC is a function of the foregoing load
information such as HII, OI, HII and the like and location information of
a user, and can be expressed in the equation of:

Pinter--ICIC=f(load_information,location_information, . .
. )

[0120] In addition to the foregoing priority weight of ICIC, a scheduling
strategy of the scheduler of a base station can further take into account
a weight PSchdl--CQI obtained from Channel Quality
Indicators (CQIs) in respective PRBs so as to perform frequency selective
scheduling:

PSchdl--CQI=h(CQIPRB, . . . )

[0121] If inter-subframe load balancing is disregarded, then a scheduling
strategy PSchdl--ICIC generally taking into account
inter-cell interference coordination can also be expressed as:

PSchdl--ICIC=η(Pinter--ICIC,PSchd-
l--CQI)

[0122] f, h and η represent different functions.

[0123] In an implementation, the following step can be further included:

[0124] The step 403 is to perform a selection strategy in each resource
dimension by the scheduler resulting from one of the resource selection
priority weight output from the interference coordination solution, the
channel information in the respective physical resource blocks and the
threshold of resource utilization ratio of inter-subframe load balancing
or a combination thereof.

[0125] In an implementation of the step 403, after considering
inter-subframe load balancing, an interference alleviation scheduling
strategy PSchdl--ICIC--.sub.subframeLB in the
scheduler taking into account joint optimization in a plurality of
resource dimensions can be expressed as

[0126] NPRB--usable is the number of PRBs useable in each
subframe in the link direction over a period of time nT˜(n+1)T.

[0127] An interference alleviation solution with joint optimization can be
created by combining inter-subframe load balancing with an interference
alleviation strategy output from various inter-cell interference
alleviation solutions, e.g., the SFR, FFR, static/semi-static ICIC, beam
coordination and the like, in a resource allocation strategy of a
scheduler as described above, and for the TDD system, this solution can
achieve a more prominent interference alleviation effect compared with
the ICIC solution alone.

[0128] Based upon the same inventive idea, embodiments of the invention
further provide a device for processing inter-subframe service load
balancing and a device for processing inter-cell interference, and since
these devices address the problem under similar principles to the method
for processing inter-subframe service load balancing and the method for
processing inter-cell interference, the implementations of these devices
can refer to the implementations of the methods, and a repeated
description thereof will be omitted here.

[0129]FIG. 5 is a schematic structural diagram of a device for processing
inter-subframe service load balancing, and as illustrated, the device for
processing inter-subframe service load balancing can include:

[0130] A service load determining module 501 configured to determine a
service load of a link over a period of time;

[0131] A threshold determining module 502 configured to determine a
threshold of resource utilization ratio according to the service load;
and

[0132] A transmitting module 503 configured to transmit service data in
respective subframes according to the threshold of resource utilization
ratio.

[0133] In an implementation, the service load determining module can be
further configured to determine the amount of data transmitted in all the
subframes in the same link direction over a past period of time when
determining the service load of the link over the period of time; and

[0134] The threshold determining module can be further configured to
determine the threshold of resource utilization ratio according to an
average usage condition of resources in each subframe over the period of
time when determining the threshold of resource utilization ratio
according to the service load.

[0135] In an implementation, the service load determining module can be
further configured to determine the amount of additional data to be
transmitted in a current link direction over a future period of time when
determining the service load of the link over the period of time; and

[0136] The threshold determining module can be further configured to
determine the threshold of resource utilization ratio according to the
amount of additional data and the spectrum efficiency of the system when
determining the threshold of resource utilization ratio according to the
service load.

[0137] In an implementation, the service load determining module can be
further configured to determine the amount of additional data to be
transmitted in each type of service or each type of RB in the current
link direction over the future period of time when determining the amount
of additional data to be transmitted in the current link direction over
the future period of time; and

[0138] The threshold determining module can be further configured to
determine the threshold of resource utilization ratio according to the
amount of additional data to be transmitted and the transmission
efficiency of each type of service or each type of RB over the period of
time when determining the threshold of resource utilization ratio
according to the amount of data.

[0139] In an implementation, the service load determining module can
include:

[0140] An RB statistic unit configured to make a statistic of the amount
of service of downlink data packets arriving of each RB over a period of
time T, datai(n); and

[0141] An RB determining unit configured to determine a service
transmission demand of the amount of additional data to be transmitted in
RBi over a future next period of time nT˜(n+1)T,
DATAi(n), according to datai(n), where RBi with a
different value of the subscript i represents a different RB.

[0142] In an implementation, the RB determining unit can be further
configured to make
DATAi(n)=βdatai(n)+(1-β)DATAi(n-1) or
DATAi(n)=datai(n) when determining the service transmission
demand of the amount of additional data to be transmitted in RBi
over the future next period of time nT˜(n+1)T, DATAi(n)
according to datai(n), wherein β is a forgetting factor, and
DATAi(n-1) is a service transmission demand of the amount of
additional data to be transmitted in RBi over a period of time
before nT˜(n+1)T.

[0143] In an implementation, the threshold determining module can be
further configured to obtain the number of PRBs used for RBi over a
period of time T, NPRBused(i,n), and then determining the spectrum
efficiency of RBi,

η i = SBR i N PRBused ( i , n ) , ##EQU00007##

according to a service bit rate of RBi, SBRi, when obtaining
the transmission efficiency of each type of service or each type of RB
over the period of time, where RBi with a different value of the
subscript i represents a different RB.

[0144] In an implementation, the threshold determining module can be
further configured to determine a downlink load threshold over a future
next period of time nT˜(n+1)T, Pth(n+1), in the equation of:

P tn ( n + 1 ) = i = 1 N 1 η i ×
DATA i ( n ) N PRBtotal ##EQU00008##

[0145] when determining the threshold of resource utilization ratio
according to the amount of additional data to be transmitted and the
transmission efficiency of each type of service or each type of RB over
the period of time.

[0146] Wherein NPRBtotal is the total number of PRBs of all the
subframes for downlink transmission of a PDSCH over the future next
period of time nT˜(n+1)T, DATAj(n) is a service transmission
demand of the amount of additional data to be transmitted in RBi
over the future next period of time nT˜(n+1)T, ηi is the
spectrum efficiency of RBi, N is the total number of RB, and
RBi with a different value of the subscript i represents a different
RB.

[0147] In an implementation, the threshold determining module can be
further configured to determine the downlink load threshold over the
future next period of time nT˜(n+1)T, Pth(n+1), in the
equation of:

[0148] Wherein Pth--min is a lower limit of the threshold
of resource utilization ratio.

[0149] In an implementation, the service load determining module can be
further configured to determine the amount of additional data to be
transmitted of each UE in the current link direction over the future
period of time when determining the amount of additional data to be
transmitted in the current link direction over the future period of time;
and

[0150] The threshold determining module can be further configured to
determine the threshold of resource utilization ratio according to the
amount of additional data to be transmitted and channel information of
each UE when determining the threshold of resource utilization ratio
according to the amount of data.

[0151] In an implementation, the service load determining module can
include:

[0152] A UE statistic unit configured to make a statistic of the amount of
service of downlink data packets arriving of each UE over a period of
time T, datai1(n); and

[0153] A UE determining unit configured to determine a service
transmission demand of the amount of additional data to be transmitted of
each UE over a future next period of time nT˜(n+1)T,
DATAi1(n) according to datai1(n).

[0154] In an implementation, the UE determining unit can be further
configured to make
DATAi1(n)=βdata1i(n)+(1-β)DATA1i(-
n-1) or DATA1i(n)=data1i(n) when determining the
service transmission demand of the amount of additional data to be
transmitted of each UE over the future next period of time
nT˜(n+1)T, DATAi1(n), according to datai1(n),
wherein β is a forgetting factor, and DATA1i(n-1) is a
service transmission demand of the amount of additional data to be
transmitted of each UE over a period of time before nT˜(n+1)T.

[0155] In an implementation, the threshold determining module can be
further configured to obtain the number of PRBs used by each UE over a
period of time T, N1PRBused(i,n), and then determine the
spectrum efficiency of each UE,

η i 1 = SBR i 1 N PRBused 1 ( i , n ) ,
##EQU00010##

according to a service bit rate of each UE, SBR1i, when
obtaining the channel information of each UE over the period of time.

[0156] In an implementation, the threshold determining module can be
further configured to determine a downlink load threshold over a future
next period of time nT˜(n+1)T, P1th(n+1), in the equation
of:

[0157] when determining the threshold of resource utilization ratio
according to the amount of additional data to be transmitted and the
channel information of each UE over the period of time.

[0158] Wherein NPRBtotal is the total number of PRBs of all the
subframes for downlink transmission of a PDSCH over the future next
period of time nT˜(n+1)T, DATA1i(n) is a service
transmission demand of the amount of additional data to be transmitted in
the UE over the future next period of time nT˜(n+1)T,
η1i is the spectrum efficiency of each UE, and M is the
total number of UEs.

[0159] In an implementation, the threshold determining module can be
further configured to determine the downlink load threshold over the
future next period of time nT˜(n+1)T, P1th(n+1), in the
equation of:

[0160] Wherein Pth--min is a lower limit of the threshold
of resource utilization ratio.

[0161] In an implementation, the service load determining module can be
further configured to set the length of the period of time depending on
the period in which a statistic of a service load level is made in
interference coordination when determining the service load of the link
over the period of time.

[0162] In an implementation, the service load determining module can be
further configured to set an uplink static period to be consistent with
or equivalent to an update period of HII and a downlink static period to
be consistent with or equivalent to an update period of RNTP if a
selected inter-cell interference coordination technology is semi-static
ICIC when making the statistic of the period of the service load level.

[0163]FIG. 6 is a schematic structural diagram of a device for processing
inter-cell interference, and as illustrated, the device for processing
inter-cell interference can include:

[0164] An inter-subframe load balancing module 601 configured to perform
an inter-subframe service load balancing process, and the inter-subframe
service load balancing process can refer to the foregoing embodiments;
and

[0165] An inter-cell interference coordination module 602 configured to
perform an interference alleviation process in one of the frequency
domain, power and the space domain or a combination thereof in combined
with various inter-cell interference coordination technologies.

[0166] In an implementation, the inter-cell interference coordination
module can be further configured to adopt the interference coordination
technologies including one or a combination of the following
technologies: SFR, FFR, static/semi-static/dynamic ICIC,
static/semi-static/dynamic beam coordination and multi-cell coordinated
scheduling.

[0167] In an implementation, the device for processing inter-cell
interference can further include:

[0168] A scheduler 603 configured to perform a selection strategy in each
resource dimension according to one of a resource selection priority
weight output from the interference coordination technologies, channel
information in respective physical resource blocks and a threshold of
resource utilization ratio of inter-subframe load balancing or a
combination thereof.

[0169] In order to facilitate description, the respective components of
the foregoing devices have been described respectively by dividing them
into various modules or units in function. Of course, the functions of
respective modules or units can be achieved in the same one or a
plurality of software(s) or hardware(s) to implement the invention.

[0170] As can be seen from the foregoing embodiments, the embodiments of
the invention propose a method and device for achieving a balance between
a system service load and an interference level across subframes in an
inter-subframe load balancing algorithm and then further achieving
interference alleviation with joint optimization in a plurality of
resource dimensions of the time domain, the frequency domain, power and
even the space domain in combination with an inter-cell interference
coordination algorithm in the time division duplex system.

[0171] Specifically, in the technical solution of the embodiments of the
invention, a multi-dimension joint interference alleviation solution of
the time division duplex system is proposed so that firstly a service
load of the TDD system is distributed evenly to respective subframes in
the same direction in an inter-subframe load balancing algorithm to
thereby achieve time-domain balance of interference, and then an
inter-cell interference alleviation strategy with joint optimization in a
plurality of resource dimensions is further achieved in the frequency
domain, power and the space domain in combination with various inter-cell
interference coordination technologies and is applied in a scheduling
strategy of a base station for the purpose of optimized interference
alleviation.

[0172] Furthermore, in the solution that the time-domain balance of
interference is firstly implemented in the inter-subframe load balancing
algorithm, a current threshold of resource utilization ratio for resource
allocation by a scheduler is generated according to a part or all of
historically statistical resource usage information, statistical amount
of data to be transmitted, an average spectrum efficiency of the system,
data transmission demands of each type of service or groups of RB in a
cell, the average transmission efficiency of each type of service or
groups of RB in the cell, data transmission demands of respective UEs,
channel quality information of respective UEs and other information, and
inter-subframe load balancing is achieved with the threshold.

[0173] Furthermore, when the threshold of resource utilization ratio
calculated in the four modes in combination with a part or all of the
foregoing information is very low, a lower limit value of the threshold
of resource utilization ratio, Pth--min, can be further
set so as to avoid any unnecessary limitation on frequency selectivity
scheduling due to the threshold.

[0174] Furthermore, in order to better combine with inter-cell
interference coordination technology, an information statistic period can
be set to be identical with or equivalent to the value of a period for
making a statistic of resource demands of respective groups of users used
in the interference coordination technology.

[0175] Furthermore, when determining the information statistic period, if
a selected inter-cell interference coordination technology is
semi-statistic ICIC, then an uplink statistic period can be set to be
consistent with or equivalent to a period of HII and a downlink statistic
period can be set to be consistent with or equivalent to a period of
RNTP.

[0176] Furthermore, after time-domain balance of interference is achieved
in an inter-subframe load balancing algorithm, in order to further
achieve interference alleviation, the inter-subframe load balancing
algorithm can be combined with various inter-cell interference
coordination technologies by which an interference alleviation effect in
the frequency domain, power and even the space domain is achieved.

[0177] Furthermore, inter-cell interference coordination technologies that
can be selected include but will not be limited to SFR, FFR,
static/semi-static/dynamic ICIC, static/semi-static/dynamic beam
coordination and multi-cell coordinated scheduling.

[0178] Furthermore, a scheduler can comprehensively take into account a
resource selection priority weight output from a selected interference
coordination solution, channel information in respective physical
resource blocks and a threshold of resource utilization ratio of
inter-subframe load balancing so as to implement an interference
alleviation solution with joint optimization in a plurality of resource
dimensions.

[0179] As can be seen, the embodiments of the invention propose an
optimized interference coordination/alleviation solution of the time
division duplex-orthogonal frequency division multiplexing system, that
is, an interference alleviation solution that joint optimization in a
plurality of resource dimensions of the time domain, the frequency
domain, power and even the space domain is achieved by combining an
inter-subframe load balancing algorithm with an inter-cell interference
coordination technology. The solution firstly addresses the drawback that
a service load of the TDD system fluctuates with respective subframes in
an inter-subframe load balancing algorithm to thereby achieve time-domain
balance of an interference level and then further achieves interference
coordination and alleviation of inter-cell interference in the frequency
domain, power and even space domain in combination with various
interference coordination solutions. Due to the presence of the
inter-subframe load balancing algorithm, the solution has a better
interference alleviation effect than the use of an inter-cell
interference coordination technology alone.

[0180] This solution can alleviate such a phenomenon that a poor
interference alleviation effect may result from load information being
not well adapted to a dynamic variation of service load across respective
subframes in the TDD system; and the solution can further alleviate
inter-cell interference in the LTE system and improve the overall
throughput performance of the system and a quality of service for users
in the system.

[0181] Those skilled in the art shall appreciate that the embodiments of
the invention can be embodied as a method, a system or a computer program
product. Therefore the invention can be embodied in the form of an
all-hardware embodiment, an all-software embodiment or an embodiment of
software and hardware in combination. Furthermore, the invention can be
embodied in the form of a computer program product embodied in one or
more computer useable storage mediums (including but not limited to a
disk memory, a CD-ROM, an optical memory, etc.) in which computer useable
program codes are contained.

[0182] The invention has been described with reference to flow charts
and/or block diagrams of the method, the device (system) and the computer
program product according to the embodiments of the invention. It shall
be appreciated that respective flows and/or blocks in the flow charts
and/or the block diagrams and combinations of the flows and/or the blocks
in the flow charts and/or the block diagrams can be embodied in computer
program instructions. These computer program instructions can be loaded
onto a general-purpose computer, a specific-purpose computer, an embedded
processor or a processor of another programmable data processing device
to produce a machine so that the instructions executed on the computer or
the processor of the other programmable data processing device create
means for performing the functions specified in the flow(s) of the flow
charts and/or the block(s) of the block diagrams.

[0183] These computer program instructions can also be stored into a
computer readable memory capable of directing the computer or the other
programmable data processing device to operate in a specific manner so
that the instructions stored in the computer readable memory create
manufactures including instruction means which perform the functions
specified in the flow(s) of the flow charts and/or the block(s) of the
block diagrams.

[0184] These computer program instructions can also be loaded onto the
computer or the other programmable data processing device so that a
series of operational steps are performed on the computer or the other
programmable data processing device to create a computer implemented
process so that the instructions executed on the computer or the other
programmable device provide steps for performing the functions specified
in the flow(s) of the flow charts and/or the block(s) of the block
diagrams.

[0185] Although the preferred embodiments of the invention have been
described, those skilled in the art benefiting from the underlying
inventive concept can make additional modifications and variations to
these embodiments. Therefore the appended claims are intended to be
construed as encompassing the preferred embodiments and all the
modifications and variations coming into the scope of the invention.

[0186] Evidently those skilled in the art can make various modifications
and variations to the invention without departing from the spirit and
scope of the invention. Thus the invention is also intended to encompass
these modifications and variations thereto so long as these modifications
and variations come into the scope of the claims appended to the
invention and their equivalents.